In recent years, in the medical and graphic arts fields, a decrease in the processing effluent of image forming materials has increasingly been demanded from the viewpoint of environmental protection as well as space saving.
As a result, techniques have been sought which relate to photothermographic materials which can be effectively exposed, employing laser imagers and laser image setters, and can form clear black-and-white images exhibiting high resolution.
Silver salt photothermographic dry imaging materials are composed of a support having thereon organic silver salts, photosensitive silver halide and reducing agents (for example, refer to Patent Documents 1 and 2, and Non-Patent Document 1.). Since no solution-based processing chemicals are employed for the aforesaid silver salt photothermographic dry imaging materials, they exhibit advantages in that it is possible to provide a simpler environmentally friendly system.
High image quality, based on enhanced sharpness, and excellent graininess and in-plane evenness, is desired to obtain sensitive delineation in medical images. Performance of high image quality has especially been demanded in order to photographically capture tumor mass shadows inside mammary glands, especially for early detection of breast cancer, employing mammography. Major improvement in this technique has long been desired, specifically since dust and foreign matter in the air or which adhere to the image film can early be misdiagnosed as calcification-like negative image (being a false image). To overcome this problem, a significant amount of dust and foreign matter is still a problem, even though commonly known removal means, such as sticky rollers are employed.
Though a technique of eliminating dust and foreign matter has improved by increasing contact pressure of the sticky rollers onto the photothermographic dry imaging materials is for example described in Patent Document 3, adhesion of dust and foreign matter recurs, since static electrification is generated when photothermographic dry imaging materials are peeled from the sticky rollers. As a result, it is easily to be understood that insufficient elimination of dust and foreign matter is obtained via this technique.
(Patent Document 1) U.S. Pat. No. 3,152,904 (Scope of Patent Claims)
(Patent Document 2) U.S. Pat. No. 3,487,075 (Scope of Patent Claims)
(Non-Patent Document 1) D. Morgan, B. Shely; Thermally Processed Silver Systems A; Imagining Processes and Materials: Neblette, 8th edition, Sturge, V. Walworth, A. Shepp edition, page 2, 1969
(Patent Document 3) Japanese Patent O.P.I. Publication No. 2003-107625 (Scope of Patent Claims)